Shut down when transitioning to battery, but will restart with battery

After a liquid spill, the computer was working normally again, except that when I unplug the power adapter, the machine shut down. After this automatic shut down, it only starts up again with the ac adapter.

So I bought a new battery.

However, when trying to change the battery, I manually shut down the machine and unplugged the AC. - Then something very strange happened: the machine booted (and ran). -- So the old battery was still ok.

I still changed the battery. Same problem. Runs with AC, but force shut downs when AC is unplugged. -- When shut down manually, can restart and run on battery.

I have done about 10 SMC resets.

Update

Okay, since people seem to be confused, again the question:

Which components are responsible for the transition from AC to battery?

DC in board, logic-board, NVRAM/PRAM? Something else? Someone with engineering background should be able to answer this.

NB: Please spare me answers like "you need to clean" / "Isopropanol works" / "you need to look under the hood" etc. I know all that. This is not helpful.

Many people ask questions here and we don't ask them up front what their skill set is. The way you ask a question is all we have to work off of. Given how you asked you didn't come off as one who could get down and deal with reading a schematic or work with SMT components. If you think your symptoms can lead you (or us) to the exact location and/or the exact component that is your problem, I'm sorry to tell you it just doesn't work that way when someone has spilled something. Sure, often we can ID a problem to a root issue if it is a common failure pattern. This is not one of those cases.

OK - Lets try a different way: can you please take pictures of your logic board (both sides and very good detailed pics at that) where you see spill damage. If you don't have any visible damage as you have already cleaned it up then the question is can you read a schematic and trace a circuit and handle soldering of SMT devices? Because thats the next step.

@skonrad, there is absolutely no reason to become rude and standoffish. Dan is most certainly trying to assist you with your water damage. I am sure there are plenty off people out here that "Someone with engineering background should be able to answer this.

NB: Please spare me answers like "you need to clean" / "Isopropanol works" / "you need to look under the hood" etc. I know all that. This is not helpful." will enjoy (not) assisting you. Remember that this is a volunteer forum, and if you do not care for the answers you receive, I suggest you take it to an authorized Apple service provider.

2 Answers

I suspect you have some corrosion or damaged component on your logic board from the spill that you missed (if you tried cleaning it up internally). If you didn't open it up you might find you have some work ahead of you (and costs).

Follow the iFixIt guide on taking the logic board out and using distilled water (not tap!) wipe down with swabs being careful not damaging anything by snagging and pull any chips off. To dry the areas you hit with water use a high grade of Isopropyl alcohol over the same spots and then let it dry a good day to be doubly sure. Also make sure you have pulled the battery as you don't want to get the board wet if it's live.

If this is to big a job for you then get your system to an independent authorized Apple support center. FYI - Apple won't touch wet systems and even the independent shops will limit their warranty on the repair.

I think you're going to have to post a picture of your board. If you think SMC resets are going to solve your spill problems, then you have a rough road ahead of you. Folks aren't likely to be able to answer your question because many components are responsible for dealing with AC and battery and while they're clustered you're probably in for a bit of solder work.